In a triangle, we use terms like adjacent and opposite. These refer to sides in relation to angles. In our musical triangle, the drummer is at one angle in the back. This side, where the audience is, is called the opposite side.
Trunc is database function, try using round for numeric values, or change the Processing of Query to database.
Signs of sine, cosine and tangent, by Quadrant. The definition of the trigonometric functions cosine and sine in terms the coordinates of points lying on the unit circle tell us the signs of the trigonometric functions in each of the four quadrants, based on the signs of the x and y coordinates in each quadrant.